吉林玉米带玉米连作障碍的根系系统自毒作用机理

Corn is an important food, feed and industrial crop. Its production in Jilin Province is China's first province and the country's major commodity grain base. Continuous cropping of corn in Jilin Corn Belt has long been used mainly for planting corn, resulting in decreasing soil organic matter content and soil fertility, reducing corn yield and quality and agricultural production costs and other barriers corn cropping. In recent years, despite the gradual increase in the amount of chemical fertilizer, but the emergence of corn production is stagnant or even decline. Even to meet the corn grow well in the environmental conditions, the maize continuous cropping obstacle can only be alleviated to some extent. Although in the past in the partial consumption of nutrients, pests and soil environmental factors and changes in non-plant study of a large number of its mechanism,the real reason has not yet been fully understood.This project can explore corn continuous cropping obstacles mechanism through simulation and field verification test from corn root system from the autotoxicity point of view. The results can provide new scientific theory for solving the corn cropping obstacles, using rationally agricultural resources, achieving high and stable yield of corn continued and pollution-free corn cultivation. The results will lay the foundation for the future to seek the way of final settlement of the corn continuous cropping obstacles and promote the development of corn cultivation and farming disciplines. The findings have also the reference significance for the formulation of the rational rotation of other crops.

玉米是重要的粮食、饲料和工业原料作物，吉林省是我国第一玉米生产大省和国家重要商品粮基地。玉米连作是吉林玉米带最普通的耕作制度，已导致土壤有机质含量和土壤肥力下降、玉米产量和品质降低及农业生产成本增加等玉米连作障碍问题。近年来，尽管化学肥料用量在逐步提高，但玉米产量却出现徘徊不前甚至下降的局面。即使满足玉米良好生长环境条件的连作，也只能在一定程度上缓解玉米连作障碍。虽然以往在养分偏耗、病虫害发生及土壤环境改变等非植物因素方面对其机理进行大量研究，但其真正原因至今尚未完全清楚。本项目通过模拟和田间验证试验从玉米根系系统自毒作用角度探索玉米连作障碍机理，以期为解决玉米连作障碍、合理利用农业资源、实现玉米持续高产稳产和玉米无公害栽培提供新的科学理论依据；为今后寻求最终解决玉米连作障碍的途径打下基础；推动玉米栽培与耕作学科的发展；其研究结果对于制定农业上其它作物合理耕作制度也具有借鉴意义。

玉米连作是吉林玉米带的主要种植制度，玉米长期连作导致土壤肥力下降、玉米产量降低及农业生产成本增加等连作障碍问题。玉米连作障碍是生产上需要解决的重要难题，其产生的机制尚不完全明确。我们认为，自毒作用是导致玉米连作障碍的主要原因之一。. 添加活性炭研究表明玉米根系分泌物及根系残体腐解液提高玉米幼苗根系中总酚含量，增加电导率，降低GPOD活性，增加MDA含量，降低叶片叶绿素含量，导致玉米根系生长受阻。多年多点田间试验表明，在控制病虫草害及充足养分条件下，连作导致玉米产量降低，尤其在干旱等逆境条件下，连作增加玉米减产幅度。深层土壤中累积多量的自毒物质显著降低深层根系生物量是玉米连作障碍中自毒危害的根本原因。鉴定出酚酸类物质是连作玉米的自毒有害物质。研究表明，轮作，施用有机肥和玉米秸秆炭是缓解连作玉米自毒危害有效措施。. 本项目研究结果为寻求解决玉米连作障碍的途径提供新的理论依据，也为完善玉米种植制度奠定科学基础，又为缓解玉米连作障碍提供有效防控措施。